SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e5b97bf8d1db2c1871ad9bb3128669bf244eed257f43d6d2bcb66650e49049f' 
  AND token = 'EzlalfCmeOP/r4jLNaFvDlz2gOV+qp+ZVXzcm2AwETw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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