SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'cb37571189309da42b404e2e98509329e361b5c310ec33fe8167adae64945a24' 
  AND token = 'qcZNz/+fm1LsI6IuygJOy/98fRabCDGyikIxeYvhSSE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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