SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6bf6f6da38097585feb6942d10dae65ef2551e84245429f9e764350a88b03e8' 
  AND token = 'wIABgxTv1hmoTaphfzn779nkVYK4wjTF/k14JKqAk+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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