SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'ec267fa2caf1e35cc0126b3bd69faf461caca8580792b314d80a94284723cb59' 
  AND token = 'nBzEmJIMsC+28s1GGDpUVfUEvRE6aUw8xfcrhOqg8HY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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