SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8b9ab73e0a87041c6ac29134ba9b271006cce69cb674c0afe5bd13002850dd1' 
  AND token = 'K5G4CgODMYEpo5uAMnrDPbmV/pnXyHYp7Mc61EIUrJs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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