SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59639420ca68529b235bbadb7e7a8fd36520df1954689bb1db65aeb6e32a6121' 
  AND token = 'XCFYPV/qFVOTpanuI/dAdQwNguaJUjNmA+dwbuNG1qo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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