SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f392441a04485d8cea0d6153163af76e3b00c101652638243246628e2650b0a' 
  AND token = 'rbH+9NIY3UqhkOu/Z7btywD/1w8ibXR7bC1U21VfpC0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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