SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58ad7459b3454cc818e76330e571e51c65df4f67ca82c698d3e5535fb6d447cc' 
  AND token = '7uHOMDwsDWjPMbBIjCe463JQnScTSUnhYS46AUDkC6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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