SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '1f4780e7ce7991d1bddf6c48cc3952bac67dfa72427276d87d2f3fce0020e856' 
  AND token = '+oAh4weieWpSK520bYOgK/MD1eEut28s7JUKRRhrmDM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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