SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '323565620390ba1fb4f14ecf77755d816669042ca29e4b86d16dc44d7f4457e9' 
  AND token = 'QN0KKouc3qzPHY2PEKnDYQiXylCaWmgLc6D6Ioc+1g0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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