SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f219da781883089467548ee9644558ff7a1f1ca081ccbb182e942112dc56e613' 
  AND token = 'P8JqwD1waBFHtEJOLAb+jqQYrAn8MDeVA56l1dwNyKE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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