SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c771a82f14cd9fb17b086e2ea435155ad2d466d648c4d099e1e217fbf5ef922b' 
  AND token = 'WwARHDE0NBGuq3VvedvYj83piZfCcSnSV6jPHF8Nkyo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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