SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'e4803872a11d12ccafb58574b2a3cb1b7475c044ca9b1dcea8ecdc9f67566ccd' 
  AND token = 'pP3VuFAT7g8gVHHRaI9JQfNSYqF7HeoY4+Z8UHKgop0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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