SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5ee989cc7520d9b6ef5de62bd4589cbb13d9661bf90044085699fb8d643d5ed' 
  AND token = '4KpwkwkwrKnIcIv7vBs/YZV5dg0mqr4X0ZVajfOFG/Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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