SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5542c82712036481095917a918805e130431a5b78adc9e1c92d8e325121604e1' 
  AND token = 'NQcqXEWGToCUxCtFdsRxsW6BCRrJ8nPijIzruvp8L0o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00060

JSON explain

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