SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '478973e26072d77e1c0bcc9c13cab458d013bc8e5c0b9f807a13fee894b3111b' 
  AND token = 'SaOBWPVZQCcSTTOu1b5Bm8A+LZOUcdXyiihHDMOsga8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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