SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a0e1dd4ad732265cca362fa2b5a0bbf654b32471f726977a80fcacd5795ac80' 
  AND token = 'J4n65drYq7pqzFd3aVITKZXcNQBnHo/lpF7pkajnswg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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