SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6adbd744c150dc4636b14c7801284f1eebbc72e60cd01630bf331055c427615' 
  AND token = '3jF+EKYbD49E+BgUD4yiYuhXbG+fGozaqWLCwmx3Iww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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