SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'e0fffe0e6981271225494679d188eabeb7c0e9666c45020f76c3ffd86535c80d' 
  AND token = 'cOsOuzBycL9n5P14xAJbyI7YUgSGvFrk+qmF7zXrMUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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