SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '5dfef98a1c50d9e19fd4788a4218dab38a3f489519c62719eece73435df43f7d' 
  AND token = 'F1XZZwNihaBSKaC+I2WjDWafy2vxfQlCPf6iU7GrpBo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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