SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d19334f5ace935be9d2753fff0426c9634c84520f21769d1b5d77a64d9f59bc' 
  AND token = '19kouh6IjBgEcQMCRO8wSeCj0LMVeIuDedWEPUkYwVo=' 
  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"
    }
  }
}