SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3089396c2d018d0df26264b7bc4db5d91d27c50353ac46ce136d2b81367be9ed' 
  AND token = 'qmxr+y8lyDHYmGPKkqgTofOSKvtWwv7VPEhJXRSz9H4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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