SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d51a4096672e4113cda80a517bdf77f239965bf504abf0e9687bf3a8ff21942' 
  AND token = 'ZQz+yST6Cz769tAB1tcBhxrDl17vglTwwzTNqrQj+FQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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