SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '248375e1463fcac48bd5702df24bf2ac921b83acbc8a25c0f0e3747da0d1288a' 
  AND token = 'kyVpWsB1nWzHALKrhsyZ2N+kCVZtftUzLYtHloW46iw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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