SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '377b9a1b91d10e2fef1f36951d43303b9fe369f2ca282e92e5273490105edff2' 
  AND token = '9ePHgOB0KAZQfRkLpZPnK76MutWU0tnkbxyDYH52nwc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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