SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ffaa456fb8d447724ef7935e51a7892c9b84dc0f9ef9197b435fb6ffd1d3cd06' 
  AND token = 'IiGJmQ72WijBeVXmCvG9L8T0NP5q9n+c1Ju/TjU76KY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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