SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2825a1ba679787ed7c4a983915fa9a24dd32b15b0b9fc3d6de527846d8604955' 
  AND token = 'k0W4hAbvSLwNeDhzrHGb5c8p1MMebFVwLkSqcxGrutA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}