SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '80daa2f688b929f4b6d455cf0cc137a2c12c4b41abd54d5807134f5e7eb435c4' 
  AND token = 'unnteR0Gxnt1CXgvqGw86jJUYAiL6y4yjFDTIpxDhOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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