SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8382118c2c1f08bacff764eab1bc5e66df11cb23040f5395259e608756206e1' 
  AND token = 'zw4xG9y3QmNgh9Ze5Uo+isGsPqnanjSTd6GUsYjbevw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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