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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19bc256ca084ad4e56e1f513dcc172828c76b1fe86edee4fd72aa3bc840d4575' 
  AND token = 'BKDO4JfYzPfiGiQtgPdSXQxp1zHm9meUNomk82gsVtQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}