SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d779a0f6b392da1c8e566d96618c35c0b7007c5951b9bbfcaffdcb49ad2053b' 
  AND token = 'g/7KJw6fXt9SPuFfLa1lUHT9blYOmbZgPrJbUAOAqwY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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