SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'ce3ab81a4a57113cc15fcb56a22fb0474ffe23d84cb662ca0a39a91c8d6c10a5' 
  AND token = 'i15+M2wjzjGwi1pw0W/zwPfQvYE/WiCpVAm53UZMkRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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