SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a209cb38c43d0ab69eb1c62914d9e7458bec4a224a8fb56eff30fa93317f9d1a' 
  AND token = '5To+mWKgLvcGEfwozlPZJ4Zc9FjAnXcUpU+xCCkySD0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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