SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5c204d3620e90cc6b51fafaf7b0391850397bd496d1b6e8c23a2e5b31e32655' 
  AND token = 'saAiYrKyqzfEsgd+CZX7ewDt7jgbGUlHcH1Lq+/IY0k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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