SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6142a12739fe4b27b3ef51cbefa969ddfa03ca94e8e75a539689a8e0e2b6788' 
  AND token = 'bvXItJp78ScZg2utCIBBEi7UASipcJVw32P2OequZlc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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