SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '250fc1b630de2124f18a6bfbb95b086bcdd5af1fcde4667815f595b58b20ccb0' 
  AND token = 'Bs2uaq6WghpTYgQvbj1UAVKooIG4YNJhaECSHA+NokE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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