SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e8a4d2d8e842950acb44ac144a1f7f5847d279db84561a968b33ee2cafb5831' 
  AND token = 'eLFr2nheFon64CsB6kWTuojXiWYIrFNOVfrbkxUGIOo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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