SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '1434d5a73fc4da134214bbbcacc385f8541e72115c2a0e678e6398adfb7d4039' 
  AND token = '5ev3axB7w5bNpq+gUs5OzeNvohjXEljCz9iX+sfvTg8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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