SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '339143974f6557f5cb05a2bac4c2a6915fcecef2ce6ab318433c794ac31c35e9' 
  AND token = 'c+qm0FibQ9yO7tZOavpY/CNjnDKz83mqSn1n9RKH9D4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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