SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70c8683453af70d4651dcf1516a30693b9fd328efb554122c519b1d7c4b5b259' 
  AND token = 'gxzGIQN4Qk3bLjbHQZ7TwQDFVp5er/h9LPdmRGeauf8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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