SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a37b227f783b4b4bbb5417deb765b4992ca2075da338197e6802e236d4dbdec0' 
  AND token = 'aKMlijm9zlbqxHeXUSBLBbJ/mJntLLfEDe6MB9MDfco=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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