SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4d1d4e716612a68b86d78b7e3e2aaabbd2eb79d5c6f988f026433b423656999' 
  AND token = 'lOTfia2teW0IQmA3MRcl+cSyUhfjCVMjaN+eMjKtq/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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