SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'dcad21334a2b50547d2ee0e6113a3c9bfd5a9800c51b5939ce589b231dbd128c' 
  AND token = 'TIzvhr3BjWV7M7LGuj6PQVhT3+qjzM+Cp6apTlTX5vg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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