SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '797603099e7f9d1c4b748b28767b7402298a286143f036ca238670f41460815e' 
  AND token = 'M36tfITZ/LtoqWxSwInyApd95kDCHQPXPFZaOWaYl/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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