SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af68ca3f4ea3eb63a2090453ebc02cf774b5ccd09b047cfdb489422d8563ed44' 
  AND token = 'XsjWX7fniaQjTdTwkrjXRMJo+7ajHnFTz3/OQsOOsFw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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