SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3709d816d82d83387e047505da9465094a01f0e802b0dd1c4a9333a54d099a84' 
  AND token = 'gmnvqNs2dZRbwunKOSVuxLYkmYKxkRawzBZZ8VfCeCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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