SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a5330db655a10caeca4bb0912e5db39ab61fa682e45f5f9f69007e1daf8ef1d' 
  AND token = 'lCDPXkhnoYlowIvRO6ZyKq+5ApiBL/cJSFK793ymr9Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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