SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0515e8b6d4cc987993ff3528b3a7f48d5d972fdec92baae51352e82372a5002' 
  AND token = '04qgbXmLlj+lNGCZSBeQvHFWYgvPW2av+v+ROUaKuqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00063

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}