SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1cc3a7d55957c2a66f2c3f5205f5008d83238f4787987f055f4a911a691f54bb' 
  AND token = 'O2WlnX2xL2uxYYNKKakMKaqW/gmljOmZFoywzsz8x7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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