SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39267ebcfa9996bb15a555be558c7e874a7204cde6678e7fdd72c9d3fe596fb8' 
  AND token = 'FIIo/XQzodg5HtMS55900dU1LGzCloiEblTjy8vX+iQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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