SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8318bdec120a8950a6599263d757e4fcd10fdeca272bcba036c91b72067439ae' 
  AND token = '3eGmzfHMgckwkkfYfdM0S6l57qNlpd1asYFwyCZFU8c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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