SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c77b2d262df92434e70fe45fd827d800966f31d43ee73d5a846ba6a8f95cb855' 
  AND token = 'f3SQM/LWW6NICiyKOouHjR2JrLmgdMeepSrJGKAuPNw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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