SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d66215391c5231cdeef388a9795463321c53feb0648a142da891d9d36dc6f82' 
  AND token = 'lIEucyUQkjkNTs7/3rbx1O+diFIpmy5zsCaRquLqe5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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