SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1245f128405827e14c8950cec99b060b68c154a8f8d01a9283d9da8e6709fc92' 
  AND token = 'MIM4h8Vlj2wviohM7kfHGgCSnWExOeKUwgc6N7xZBIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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