SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f58b00062d1166922a381350e907c9a7342ff2fa527650a92fe3e2e03922cf59' 
  AND token = 'K8UckTwspBz8N1/YhOOI9vqjUieWaPVO8anLyAloelg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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