SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c702bc2d1b9e3d15f5cf8ee45e957ebf3eb904551793763c675703fb1e3a4307' 
  AND token = 'BhkVqgoaxd7MQI0OPVYaiqs0v/x9HHeLIgjWeOgwdYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}