SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d913db5e2b276353b740e3e6993bfac7246aba04d274bbd02f0a17a587afecb' 
  AND token = 'kdl3T2py50mJdif6TnwlbvKftMs6v3nHivxxWUTIeRA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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