SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7348ccb940f1e6c1d023c5c0d879ce300d32b14d2277813834e0979263a9a4a7' 
  AND token = 'ttF35DQ7g4o0LL5VhyV9SVqmshUqLwOVPOxiXIChs3E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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