SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3e8f8b66c0fba79a2203d3470952e53282fb537f83caa64d6a0eeea197c80f97' 
  AND token = 'QjDVaW2YJrqwIFXfhxsQSttw/QWtu3MYSwi/dpQoGQ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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