SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6708f7afb292410be48bc4a85681727aaff765184c980d8bfa181588f7c6f2b3' 
  AND token = 'zU6/F2QLgzVPPFc6orIxvJUmnRi2NUv0FL4vJhKbwY8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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