SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b83717564b1cbdb2d0eac7aecea6a0251773069d5561f20f24663895459e9219' 
  AND token = '1FOpXLtJpTFQL/gciIo6MNy6tZm2HzfrHRX8EJqvxkc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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