SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8d027e0aac2879dcf9278ad2d48fc9cf304f37ccb1fffd9f8288b876cd7be81' 
  AND token = 'QB4AysvOMAWke75hW1JI/ww4E5jX1Gv+4Eoeq47yDX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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