SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6c4498e22668503de7912c61436fa99c2eb407f3591f6d3a75076218d18458d' 
  AND token = 'HpXdjJWjuXmxU5Y7j8wTpwbkwzqZ2RByaY9Zmm0KrZs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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