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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4732fd12eb58304d1a5dfb76fdf137d5b312e37b461fc00f0ab2a1d9a1c4d17' 
  AND token = '2LyXtHzJdc75lCuqQdOF4XzFeVarYFeL97a1qWExN9I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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