SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f493b099fa5b594a69cc674acfab04ff08ec98f2ee5dca646a782146666289bc' 
  AND token = 'WWchP3SfZvseFUlV98/WfwwH4FRyHSAAYp6rLESCvD0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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