SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f15f553f516233e7bc38b2826672c3cbe1144c72f0480e78fd3a6f1b98a8f8d7' 
  AND token = 'MBOxuL4gchKHFz4E0FBX1GkWr+FPwKyB+0FPHFzZhqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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