SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ab0ba1c29c6b275147aceaef46eafab5c11d7468ec7bc01be4481d98ed06f25' 
  AND token = 'wSIUBs8h+GcOSYkEK4lmTkQmeH29uMaPTxvMnGp25M4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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