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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12ca7a73ca963f95800e736d28d1dcd62399a354fc350dc36589e2ee3a5a7f7d' 
  AND token = 'jyUsDGrAfLfNEkcKUoIuYzYsBio9d1GpYbsvRj/m+ZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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