SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a3af310472f6ec8a30094e4319b3d7215a58792aac10b8ff18f453a2f6439735' 
  AND token = 'VI6YLTQCfLFtXzOk/cehBa9TICiSZgNG5qo8Z9Rt+Ks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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