SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4a6d65d9dcaad404e1e174d672049efdd256914802321c040df7a6770acdec6b' 
  AND token = '3HuVkoO9+SDHm2DuhuUmhuArDOB3ejG5IW2XXjhoj30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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