SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f07571794221424fba4635f2ffd36ae3ca55aa5713d00cf30e050062594fd8d8' 
  AND token = '91bua5dM7rZ3caX2C1f3RLfjZLHJGNUFEYjmCcoRJOU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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