SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'd8ce9518cf98ffc6e06995b6d83f833d2937abde15463526b7b792e4d933a0a9' 
  AND token = 'eemokymgDIO66Y6QpcDfG5Ma1GC7uE9oNXDOmQhZraw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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