SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dbfd01e6600d3e3f06a5a14e664e8613ebfc6842e4bd9974836586411cde599c' 
  AND token = 'sOpOjMexQzOoRCQwagpp4khvvpmXrlw1WsERqDBoA88=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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